PRINCETON, N.J.—Envigo has announced that it is launching the R2G2 mouse during the American Association for Cancer Research (AACR) annual meeting in
Washington D.C., held April 1-5. The R2G2, a Rag2/IL2RG double-knockout model, was created by backcrossing the common gamma chain gene mutation (IL2RG) on to
a unique C57BL/6 and 129 mixed background mouse with a mutation in the recombination activating gene 2 (Rag2). The R2G2 mouse addresses common challenges
that researchers experience with current models used in oncology, immuno-oncology and infectious disease research.

The R2G2 is said to provide distinct advantages over other triple immunodeficient models with thescid mutation. One key benefit that reportedly
makes it ideal for oncology research is the model’s reduced radiosensitivity, meaning it has the ability to tolerate the effects of a wider range of
radiation dosages. This helps researchers more closely simulate the treatment environments of cancer therapies, where patients receive combinations of
chemo/immunotherapy and radiation. The model is highly immunodeficient due to the lack of functional T cells, B cells and natural killer cells resulting from
the Rag2 and IL2rg gene disruptions.

Envigo also touts the R2G2 added benefit of reduced “leakiness”
when compared to several other models with the scid mutations—models whose immune systems regenerate as they age, forming new T cells, which can
confound experiments.

“R2G2 is a genetically engineered model (GEM) and its launch forms part of
Envigo’s wider commitment to expand the number of GEMs in our portfolio, and provide researchers with new models that address limitations they
encounter with other mice currently used for research in oncology and infectious disease,” said Mike Caulfield, president of contract research services
and research model services in North America at Envigo. “Already, radiosensitivity testing has proven this model is less sensitive and flow cytometry
has demonstrated that the immune profile is similar to the NSG model.In short, R2G2 provides a translational research approach that will help customers to
more accurately predict outcomes.”

In addition to the experiments already completed, Envigo is currently
validating the model’s potential humanization benefits, the outcome of which is expected to be announced in early summer. Data that Envigo has compiled
on the R2G2 is outlined in a white paper that is being distributed at AACR and also via Envigo’s website. Envigo will continue to collect data on this
model and wishes to collaborate with researchers who are willing to provide insights about the R2G2 mouse based on its use in studies.